Update PoC parser with AST

lib/Alchemy/Phrasea/SearchEngine/Elastic/AST/TextNode.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace Alchemy\Phrasea\SearchEngine\Elastic\AST;
+
+class TextNode extends Node
+{
+    protected $text;
+
+    public function __construct($text)
+    {
+        $this->text = $text;
+    }
+
+    public function getQuery($field = '_all')
+    {
+        return array(
+            'match' => array(
+                $field => $this->text
+            )
+        );
+    }
+
+    public function __toString()
+    {
+        return sprintf('"%s"', $this->text);
+    }
+}